Electrochemical machine apparatus

ABSTRACT

AN ELECTROLYTIC DEMETALLIZING APPARATUS FOR SHAPING A WORKPIECE WHICH IS HELD BY A TABLE ON A WORK-SUPPORTING SURFACE. AN ELONGATED MEMBER EXTENDS UPWARDLY THROUGH AN APERTURE IN THE TABLE IN A DIRECTION GENERALLY PERPENDICULARLY TO THE WORK-SUPPORTING SURFACE, AND CARRIES AN ELECTROLYTIC SHAPING CATHODE WHICH IS USED TO ERODE A WORKPIECE. GENERALLY, THE TABLE IS ROTATABLE ABOUT AN AXIS PERPENDICULAR TO THE WORK-SUPPORTING SURFACE TO PERMIT THE WORKPIECE TO BE ROTATED WITH RESPECT TO THE CATHODE FOR EASE IN PRESENTING THE LOCATION TO BE SHAPED ON THE WORKPIECE TO THE SHAPING CATHODE. THE TABLE OR THE ELONGATED MEMBER IS CAPABLE OF MOVING IN DIRECTION GENERALLY PARALLEL TO THE WORK-SUPPORTING SURFACE TO BRING THE SHAPING CATHODE INTO CLOSE PROXIMITY WITH THE WORKPIECE, WHILE PRESSURIZED LIQUID ELECTROLYTE IS PASSED THROUGH THE SHAPING CATHODE AND BETWEEN THE WORKPIECE AND THE CATHODE, AND A D.C. VOLTAGE IS MAINTAINED ACROSS SAID WORKPIECE AND SAID SHAPING CATHODE IN A SENSE TO MAKE THE WORKPIECE ANODIC.

March 30, 1971 A. WILLIAMS ET AL 3,573,188

. ELECTROCHEMICAL MACHINING APPARATUS Filed Jan. 51; 1968 4 Sheets-Sheet 1 v March 30, 1971 L. A. WILLIAMS ETAL 3,573,188

ELECTROCHEMICAL MACHINING APPARATUS 4 Sheets-finest 2 Filed Jan. 31 1968 arch so, 1971 L. A. WILLIAMS ET AL 3,573,188

ELECTROCHEMICAL MACHINING APPARATUS Filed Jan. 31, 1968 4 Sheets-Sheet 5 ArrO'QN -F March 30, 1971 L. A. WILLIAMS ET AL 3,573,188

ELECTROCHEMICAL MACHINING APPARATUS Filed Jan; 31, 1968 4 Sheets-Sheet 4 mlumvraes 3 573,188 ELECTROCHEMICAL MACHINING APPARATUS Lynn A. Williams, Winnetka, Leonard R. Malkowski, La Grange, and Sigmund H. Bielak, Downers Grove, Ill.,

assignors to Anocut Engineering Company Filed Jan. 31, 1968, Ser. No. 701,885 Int. Cl. B23p 1/02 US. Cl. 204-224 12 Claims ABSTRACT OF THE DISCLOSURE An electrolytic demetallizing apparatus for shaping a workpiece which is held by a table on a work-supporting surface. Anelongated member extends upwardly through an aperture in the table in a direction generally perpendicularly to the work-supporting surface, and carries an electrolytic shaping cathode which is used to erode a workpiece. Generally, the table is rotatable about an axis perpendicular to the work-supporting surface to permit the workpiece to be rotated with respect to the cathode for ease in presenting the location to be shaped on the workpiece to the shaping cathode. The table or the elongated member is capable of moving in a direction generally parallel to the work-supporting surface to bring the shaping cathode into close proximity with the workpiece, while pressurized liquid electrolyte is passed through the shaping cathode and between the workpiece and the cathode, and a DC. voltage is maintained across said workpiece and said shaping cathode in a sense to make the workpiece anodic.

BACKGROUND OF THE INVENTION The field of electrolytic demetallizing is a rapidly growing and diversified art, a broad description of the field being supplied by US. Pat. No. 3,058,895. Basically, a cathode is brought into adjacent relation with an electrically conductive metal workpiece while liquid electrolyte is passed under pressure across the gap between the cathode and the workpiece, the electrolyte passing to the exterior by any of several known means. (See US. Pat. 3,254,013.) Electric current is passed between the cathode and the workpiece, through the rapidly moving stream of electrolyte, in a sense to make the workpiece anodic. Under these conditions, the workpiece can be smoothly eroded to define a shape which is determined by the shape of the cathode. A large variety of shapes can be produced in this manner, e.g. turbine blades, dies, and other complex parts.

This application relates to an apparatus and method for holding and positioning a workpiece and a shaping cathode during electrolytic demetallization processes. The apparatus of this invention is particularly useful for electrochemically eroding hollow workpieces Which have at least one opening to the exterior. By means of this apparatus, the cathode is placed inside such a workpiece to demetallize portions of the interior. In addition, the apparatus of this invention can be used to demetallize exterior portions of the same workpiece.

Typically, the device of this invention can also be used to quickly and efiiciently machine several portions of a workpiece which are precisely located with respect to each other. This is accomplished through the use of an opencenter rotating index table upon which the workpiece rests. Each location of the workpiece which is to be machined can be quickly and accurately presented to the shaping cathode simply by rotating the index table until the workpiece reaches the desired position, and then locking the table to prevent further rotational movement.

United States Patent The apparatus of this invention can be used to machine both the inside and the outside of cylindrical parts such as those used in aircraft jet engines, which fre quently require electrochemical machining operations to produce bosses or airfoil shapes of various kinds on both the inside and outside thereof. A large number of machining operations can be quickly performed on a cylindrical workpiece, or on other open, hollow workpieces, using the apparatus of this invention.

SUMMARY OF THE INVENTION In accordance with this invention an apparatus for electrochemically machining a conductive metal workpiece is provided which contains a table having a worksupporting surface upon which a workpiece can be held. An elongated member extends through an aperture in the table in a direction generally perpendicular to the worksupporting surface, and is capable of holding a hollow electrolytic shaping cathode at a position spaced from the workpiece in a direction generally parallel to the worksupporting surface. Typically, the work-supporting index table is capable of rotating about an axis perpendicular to the work-supporting surface, to rotate the workpiece.

A hollow workpiece which has an opening to the outside can be affixed to the table so that the opening in the workpiece faces the aperture in the table. In this situation, the elongated member can pass through the aperture and the opening to hold the shaping cathode at a position inside of the workpiece. Alternatively, the workpiece can be positioned on the table along side the elongated member so that the shaping cathode can machine the exterior of the workpiece.

The elongated member or the table is capable of moving in a direction parallel to the work-supporting surface to bring the workpiece and the shaping cathode into close proximity to each other in order to effect electrolytic demetallization.

The apparatus of this invention also has been for connecting a source of direct current across the workpiece and cathode in a sense to make the workpiece anodic, while pressurized liquid electrolyte is provided to pass through the shaping cathode and between the workpiece and the shaping cathode when they are in close proximity with each other.

The apparatus of this invention can also contain means for raising and lowering the elongated member in order to further simplify the problem of engagement of the shaping cathode with the precise spot on the workpiece which is to be machined.

DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation of one embodiment of the apparatus of this invention, prepared to machine the interior of a workpiece.

FIG. 2 is a perspective view of another embodiment of the apparatus of this invention, which includes a rotatable indexing table for supporting a workpiece in a desired angular position.

FIG. 3 is a sectional view of the apparatus of FIG. 2, taken along the line 3-3 in FIG. 2.

FIG. 4 is a side elevation of the apparatus of FIG. 1 prepared to machine the exterior of a different workpiece.

FIG. 5 is a sectional view, greatly magnified, taken along line 5-5 of FIG. 2.

FIG. 5a is a greatly magnified view of the vicinity of aperture 82 of FIG. 5.

FIG. 5b is the same magnified view of a portion of FIG. 5 except that it shows a different phase of operation.

FIG. 6 is a section of the apparatus of FIG. 3, taken along line 6-6 in that figure, showing one side of the rotatable indexing table and the structure upon which it rests.

FIG. 7 is a fragmentary plan view of the locking mechanism for the rotatable indexing table of the apparatus shown in FIG. 2.

FIG. 8 is a fragmentary, longitudinal, sectional view of a movable tooling post which is usable in other embodiments of the machine of this invention.

FIG. 9 is a side elevation, partly in section, of the top part of the tooling post 8 of FIGS. 1 and 4.

DESCRIPTION OF SPECIFIC EMBODIMENTS FIGS. 1 and 4 disclose an apparatus for electrolytically demetallizing both the inside and the outside of hollow workpieces. Workpiece 2, shown in FIG. 1, is generally cylindrical, having a plurality of integral bosses or studs 4 which are to be machined to a precise configuration that conforms to the shape of electrolytic shaping cathode 6. Cathode 6 is held by tooling post 8, which in turn is rigidly afiixed to the frame of the machine.

Workpiece 2 is bolted or clamped to a moving table 10, which is slidable on track 7 (shown in phantom), so that workpiece 2 can move with respect to tooling post 8 and shaping cathode 6. The moving table 10 has an aperture or slot 10A through which the tooling post 8 projects upwardly. The slot permits the table to move with respect to tooling post 8 to bring workpiece 2 and cathode 6 into close proximity during the electrochemical ma chining process.

The motion of table 10 is controlled by drive motor 12 and drive screw 14, which latter member penetrates the moving table 10 to engage a threaded drive nut (not shown). As will be seen, rotation of the drive screw causes boss 4 to move horizontally toward or away from cathode 6 as desired.

During the electrolytic shaping process, sliding cover 16 is moved into position covering and surrounding workpiece 2, tooling post -8, and cathode 6 to prevent splashing of electrolyte. Pressurized electrolyte is fed into hollow shaping cathode 6 through conduit 18 which leads from a source of pressurized electrolyte. The electrolyte passes out of cathode 6, and then between the cathode and boss 4 under high pressure. At the some time, direct current is passed between cathode 6 and workpiece 2, in a sense to make the workpiece anodic, by means of cables 22 and 23 which lead to an electric current source.

Electrochemical machining takes place when moving table 10 is moved by motor 12 to bring workpiece 2 and cathode 6 into close proximity to each other under the conditions just described. As the electrolytic demetallization progresses, boss 4 assumes the contour of the shaping cathode 6. To maintain high pressure electrolyte flow between cathode 6 and boss 4, the workpiece is caused to advance against the electrode by moving table 10 at a steady rate of speed as electrochemical demetallization takes place, until the desired shape has been achieved. The electrolyte flows into storage tank 9 after passing out of cathode 6.

As indicated, FIG. 1 shows a machine of this invention prepared for machining the inside of workpiece 2. FIG. 4 shows the same machine prepared for machining the outside of another workpiece 2W. The workpiece 2W has been placed on table 10 so that it does not surround tooling post 8. Motor 12 then draws table 10 and workpiece 2W toward tooling post 8 to demetallize the exterior of the workpiece.

The same workpiece can be machined on both the inside and the outside by the apparatus of this invention upon proper selection of the relative dimensions of the workpiece and the apparatus.

FIG. 9 shows a magnified view of the top part of tooling post 8 to illustrate how the shaping cathode 6 can be attached to either side of tooling post 8 and how fine adjustments can be made in the position of the shaping cathode.

Tooling post !8 includes outer portion 11, conductive core 13, and cap 9. Cap 9 and. outer portion 11 are made of an electrically insulating material. Outer portion 11 surrounds the conductive core 13 through which the electric current passes to the shaping cathode 6. The conductive core is typically made of a solid piece of copper, and has a head 13H which is not surrounded by outer portion 11.

Conductive face plates 15 are attached to head 13H in close contact to permit the fiow of electrical current therebetween. Loosely fitting bolts 15B hold face plate 15 to head 13H while permitting the face plates to slide vertically and horizontally for a short distance in a plane parallel to the faces of head 13H which abut against the face plates 15. This freedom of motion of bolts 15B can be utilized to make the final position adjustment of the shaping cathode 6 which is attached to the face plate 15. The vertical adjustment of each face plate is controlled by vertical adjustment bolts 15V, while horizontal adjustment is controlled by horizontal adjustment bolts 15H, which are held by cross member 17. Member 17 is afiixed to outer portion 11.

An electrolytic shaping cathode 6, connected to an electrolyte conduit 18, can be bolted or otherwise attached to either of the face plates 15 to form an electrical connection with core 13.

FIGS. 2, 3, 5, 6, and 7 disclose an apparatus which has a table 24 capable of both lateral motion and rotary motion so that workpiece 25, a fragment of which is shown in phantom lines in FIG. 2, can be rotated to present to the shaping cathode the portion of the workpiece which is to be machined. I

Tooling post 27 extends through aperture 24A in moving table 24 and is adapted to carry a shaping cathode, which is not shown in FIG. 2 in order to clarify the drawing.

Table 24 contains base 26 upon which support ring 29 and rotatable ring 28 are carried. Pads 30 are carried by rotatable ring 28 to define a flat surface to which the workpiece 25 is afiixed.

Shot pins or toggle clamps 32 prevent ring 28 from rotating while the electrolytic shaping process takes place. Cover 34 slides on rails to enclose table 24, workpiece 25, and tooling post 27 during the electrochemical machining operation.

Housing 36 encloses the drive means for laterally moving table 24. Pan 38 holds expended electrolyte.

FIG. 3 gives a sectional view of the apparatus shown in FIG. 2.

Tooling post 27, containing conductive member 27M, carries shaping cathode 40 in contact with the conductive member. Cathode 40 is connected by conduit 42 to a source of pressurized fluid electrolyte. Generally cylindrical workpiece 25 is affixed to pads 30 by bolts 31. Pads 30 are attached to ring 28, while ring 28 rests upon and is rotatable with respect to support ring 29, which, in turn, is aflixed to base 26.

Base 26 is slidable in a horizontal direction, facilitated by a plurality of bearings 48 which roll on hardened way 49 attached to wall 46, shown in cross-section in FIG. 6. A typical bearing which can be used consists of a loop of roller bearings which run on ellipsoidal track and which are affixed to the base 26 by bearing support 47. Drive motor 50 operates drive screw 52 through a gear reducer 51 to advance the table 24 along wall 46.

A similar horizontal sliding mechanism is found on the other side of table 24, so that the table 24 actually slides on two parallel walls 46.

Boss 54, which is part of workpiece 25, is indexed by the rotary motion of table 24 into a position directly in front of shaping cathode 40, and then the horizontal motion of table 24 brings boss 54 into close proximity with shaping cathode 40 during the electrochemical machining process.

Direct electric current is passed between cathode 40 and workpiece 25 in a sense to make the workpiece anodic, the current being provided by cables 56 and 58,

which lead to a direct current source. Cables 58 are electrically connected to conductive member 27M, and lead away from the immediate area of the electrochemical machining inside of tooling post 27.

Bearings 48 and hardened way 49 are protected from contact with the electrolyte, and resultant corrosion, by extensible boots 60 which expand and contract in accommodation to the lateral position of table 24.

FIG. shows more details of how ring 28 and pads 30 can be rotated with respect to support ring 29. FIG. 5 also shows the rotating drive means, and locking means for preventing rotation of the table during electrochemical machining operations.

Pad 30, which is bolted to ring 28, carries a thin coating 62 of electrically insulating, noncorrodible material, such as epoxy resin filled with fibrous glass, on all of its exposed faces to prevent corrosion in the presence of the liquid electrolyte. This coating 62 is also carried on the exposed portions of ring 28. The upper surfaces of the various pads 30 are adjusted to occupy a single plane by inserting shims as needed between the pads and ring 28 so that the workpiece is level when attached to the pads. Threaded holes 64 in pad 30 can be used to attach clamp means for holding the workpiece, or to attach the workpiece itself, as desired.

Pneumatically-operated toggle clamp 32 presses bar 66 downwardly against hardened steel ring 68 during the electrochemical machining process, to prevent ring 28 from rotating. When it is desired for ring 28 to rotate, the toggle clamp 32 is actuated to raise bar 66, and crank means 69 is used to rotate gear 70 through right angle link 72. The rotation of gear 70 is transmitted to outer, circular race 74, which carries gear teeth to engage gear 70, and which is attached to and rotates ring 28. The outer race 74 rotates about ball bearings 76 and inner, circular race 78 which is attached to support ring 29. If desired, an electric motor or other power means can be used to supplement or to replace the crank means 69 shown herein for rotating ring 28.

Optionally, at another point about the circumference of outer race 74, a system similar to gear 70 and link 72 can be used to transmit the rotation of outer race 74 to a Rotopulser to give a precise readout of the angular position of ring 28. Using the Rotopulser, the operator can rotate the rotating table until the desired angular readout shows on the Rotopulser and then clamp the table by means of toggle clamp 32, thus precisely locating the workpiece with respect to its angular position for accurate machining.

The rotation of ring 28 is assisted by a series of air pressure devices 80, which permit rotating ring 28 to rise off the surface of support ring 29 by providing a blanket of compressed air between the two rings. As best seen in FIGS. 5a and 5b, side channels 81, which are connected to a source of compressed air, lead to apertures 82 in the upper surface of support ring 29. Each of apertures 82 opens downwardly into a chamber 81a in support ring 29, located at the end of each channel 81, each of which chambers holds a ball bearing 83. The top wall of the chamber flares downwardly and outwardly from aperture 82. The bottom wall of chamber 81a defines a horizontal ledge about the end of channel 81. The aperture 82 is of sufiicient size that ball 83 can protrude about 1 to 2 mils above the upper surface of support ring 29, while the ball 83 is large enough not to roll into side channel 81 when air is not passing through channel 81, the situation shown in FIG. 5a. This system is conventional and known. The chamber is of sufiicient size to permit the ball to engage in a small amount of movement.

When it is desired to rotate ring 28, air pressure is applied to channels 81. The pressurized air passes around ball 83 and out aperture 82, since the ball is prevented from completely obstructing aperture 82 by the fact that ring 30 still rests upon the upper surface of support ring 29, and thus prevents the ball from moving completely into the aperture. As air passes out aperture 82, ring 28 is slightly raised by the air pressure, as shown in FIG. 5b, and is easily rotated while resting on the resulting blanket of air.

The air pressure device just described has a self-leveling feature in that when any part of ring 28 rises more than one or two mils, the balls 83 in the area underneath the rising portion of ring 28 move upwardly to obstruct aperture 82, thus choking the flow of air and causing that portion of ring 28 to drop again. As soon as ring 28 does drop, its underside forces the ball 83 out of obstructing engagement with aperture '82, permitting air to flow once again through the aperture until equilibrium is reached.

Thus, a plurality of the above air outlets distributed in a uniform manner about the upper surface of support ring 29 will permit ring 28 to rise upon application of air pressure, and to remain level on a blanket of air while being rotated.

Electrolyte is prevented from creeping into the area be tween rotatable ring 28 and support ring 29 by the interaction between bafiles and 92, respectively, and inner and outer, air-expandable, rubber rings 94 and 96. The latter members are filled with air during the electrochemi' cal machining process to expand outwardly, and engage bafiies 9t) and 92, respectively, with a fluid-tight seal. When it is desired to rotate ring 28, the rings 94 and 96 are deflated to reduce frictional drag.

FIG. 6 is taken along line 6-6 in FIG. 3, and shows a cross section of one side of the moving table 24. FIG. 6 particularly illustrates the means for effecting horizontal motion of the table. As was also shown in FIG. 5, pads 30 are afiixed to rotating ring 28 which in turn rests upon support ring 29. Support ring 29 is attached to base 26, which is attached to bearing support 47 for holding bearings 48 which move along hardened ways 49. The hardened ways are carried by supporting wall 46.

Splash shield 98 rolls in a horizontal direction on roller and track assembly 100 from the open position shown in FIG. 2 to a closed position over the tooling post 27 and moving table 24 of this apparatus. Labyrinths 102 and 103, which have generally vertical Walls, prevent electrolyte from penetrating into the region occupied by bearings 48 and hardened ways 49, where the electrolyte would cause corrosion. At the same time, the labyrinths permit the table assembly 24 to slide with respect to wall 46 and tooling post 27.

Channel 104 collects electrolyte which has passed between the workpiece and the shaping cathode, the channel leading into electrolyte collection pan 38 (shown in FIG. 2) to carry expended electrolyte away from the electrolytic shaping region of the apparatus.

FIG. 8 discloses a different embodiment of the apparatus of this invention. The previous embodiments have disclosed a moving table and a fixed tooling post for holding a shaping cathode. This structure embodies a table which does not move horizontally, and a tooling post which is movable both vertically and horizontally. The horizontal motion of the tooling post is used to bring the shaping cathode into close proximity with the workpiece for electrochemical machining, while the vertical motion of the tooling post simplifies the problem of bringing the shaping cathode to bear against the precise spot on the workpiece which is desired to be machined. Alternatively, the horizontal motion may be used for positioning and the vertical motion for machining.

A rotating index table 124 is carried by fixed frame assembly 126, both the table and the assembly defining an aperture 129 through which the movable tooling post 127 protrudes. The tooling post comprises a cathodecarrying assembly 130 and a vertical sliding member 132, which slides upon bearings 134 which roll between the vertical sliding member 132 and hardened ways 136 to permit the tooling post 127 to slide vertically.

The tooling post 127 extends upwardly through an aperture 129 in horizontal sliding member 13 8. Member 138 slides on bearings 140' which roll between sliding member 138 and hardened ways 142. Hardened ways 136 are carried by sliding member I138, so that the tooling post 127 moves horizontally with the horizontal sliding member 138.

The horizontal sliding member 138 is driven in a horizontal direction by the cooperative action of drive screw 144 and drive nut 144N, which nut is rotated by motor 145 and gear reducer 14 7 to impart horizontal motion to the drive screw and member 135.

Vertical motion of tooling post 127 can be imparted by the action of motor 146 and gear reducer 149, or by a hand crank in lieu of the motor and gear reducer if desired. These members impart rotary motion to extensible spline shaft 148. The rotating spline shaft in turn rotates drive screw 150 through right angle link 1522. The drive screw 150 cooperates with drive nut 154, which is affixed to sliding member 132 to move the entire tooling post 12 7 vertically.

To operate the above apparatus, a workpiece is affixed to rotating table 124 and indexed by rotary motion until the portion desired to be electrolytically machined faces a shaping cathode which is carried by post 130 and which cathode is connected to an electrolyte source. The vertical position of tooling post 127 is adjusted so that the shaping cathode and the portion of the workpiece to be machined are in a line parallel to the direction of horizontal motion of member 138. Then horizontal member 138 is driven by screw 144 to move tooling post 127 laterally. This brings the shaping cathode into close proximity with the workpiece for electrochemical machining. Direct current can be applied across the shaping cathode and workpiece in any conventional manner.

From the foregoing, it will be observed that numerous variations and modifications may be affected without departing from the true spirit and scope of the novel concept of the invention. 'It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.

That which is claimed is:

1. An apparatus used in electrochemically machining a conductive metal workpiece which comprises: a table having a work-supporting surface, said table having an aperture in said surface; means for holding the workpiece on said work-supporting surface; an elongated member extending throu h said aperture in a direction generally perpendicular to said work-supporting surface; an electrolyte shaping cathode; means for holding said electrolytic shaping cathode on said elongated member in a position spaced from said workpiece and extending generally parallel to said Work-supporting surface; means for displacing said table and said cathode holding means with respect to each other to bring said workpiece and said cathode into close proximity with each other; and means for connecting a source of DC voltage across said workpiece and said cathode to make said workpiece anodic.

2. The apparatus of claim 1 which includes means for passing pressurized liquid electrolyte between said shaping cathode and said workpiece when said workpiece and cathode are in close proximity to each other.

3. The apparatus of claim 1 in which said displacing means comprises means for moving said elongated member in a direction parallel to said work-supporting surface.

4. The apparatus of claim 1 in which said displacing means comprises means for moving said table along a path generally parallel to said work-supporting surface.

5. The apparatus of claim 1 which includes means for moving said elongated member in a direction which is generally perpendicular to said work-supporting surface.

6. The apparatus of claim 1 which includes means for rotating said table about an axis perpendicular to said work-supporting surface, said axis being located within said aperture.

7. The apparatus of claim 6 which includes means for passing pressurized liquid electrolyte between said shaping cathode and said workpiece when said workpiece and cathode are in close proximity to each other.

8. An apparatus used in electrochemically machining a conductive metal workpiece which comprises: a table having a work-supporting surface, said table defining an aperture in said surface; means for rotating said table about an axis perpendicular to said work-supporting surface, said axis being located within said aperture; means for holding the workpiece on said work-supportin surface; an elongated member extending through said aperture in a direction generally perpendicular to said worksupporting surface; a hollow, electrolytic shaping cathode; means for holding said hollow, electrolytic shaping cathode in a position spaced from said workpiece in a direction generally parallel to said work-supporting surface; means for moving said table along a path generally parallel to said work-supporting surface to bring said workpiece and said shaping cathode into close proximity with each other; and means for connecting a source of DC. voltage across said workpiece and said cathode to make said workpiece anodic.

9. The apparatus of claim 8 which includes means for passing pressurized liquid electrolyte through said shaping cathode and between said workpiece and said shaping cathode when said workpiece and cathode are in close proximity to each other. i

10. An apparatus used in electrochemically machining a conductive metal workpiece which comprises: a table having a work-supporting surface, said table havin an aperture in said surface; means for rotating said table about an axis perpendicular to said work-supporting surface, said axis extending through said aperture; means for holding the workpiece on said work-supporting surface; an elongated member extending through said aperture in a direction generally perpendicular to said worksupporting surface; a hollow, electrolytic shaping cathode; means for holding said hollow, electrolytic shaping cathode on said elongated member in a position spaced from the workpiece and extending generally parallel to said work-supporting surface; means for moving said elongated member in a direction parallel to said worksupporting surface to bring said workpiece and said shaping cathode into close proximity with each other; and means for connecting a source of DC voltage across said workpiece and said cathode to make said workpiece anodic.

11. The apparatus of claim 10 which includes means for passing pressurized liquid electrolyte through said shaping cathode and between said workpiece and said shaping cathode when said workpiece and cathode are in close proximity to each other.

12. The apparatus of claim 10 having additional means for moving said elongated member in a direction generally perpendicular to said work-supporting surface.

References Cited UNITED STATES PATENTS 3,214,360 10/1965 Bender ct a1. 204224 2,927,521 3/1960 Smith 204-199 2,526,423 10/1950 Audorff.

JOHN H. MACK, Primary Examiner S. S. KANTER, Assistant Examiner US. Cl. X.R.

Dedication 3,573,188.Lynn A. Williams, Winnetka, Leonard R. Malkowskz, La Grange,

and Sigmund H. Bielals, Downers Grove, Ill. ELECTROCHEMI- CAL MACHINING APPARATUS. Patent dated Mar. 30, 1971. Dedication filed Dec. 23, 1971, by the assignee, A'noaut Engineering Company. Hereby dedicates to the Public the portion of the term of the patent subsequent to Dec. 24, 1971.

[Ofioz'al Gazette April 25, 1972.] 

